Just Pulled The Trigger on DSJ

On another thread regarding the DS SR the same hiss/hum kind of noise I experienced with my DSJ was fixed by running the DAC through a preamp. I was running mine directly to my amp.

Yikes; this is VERY disconcerting to hear!

One…I’m with Andolink; there are plenty of good units out there…that don’t need, external cooling. That’s the tail wagging the dog, IMO. Now…I don’t stack units, like Andolink seems to have his; and a comment like “That won’t work for me for two reasons: 1. There’s no space on the shelf my gear sits on”…tells me, maybe…he’s got his gear, pretty tightly packed in a cabinet? Not the way I roll; so I’m hoping, that’s a concern (like, I’d prefer it ran cooler), but not an issue.

This noise thing, OTOH; is a deal-breaker…if true. I can’t tolerate, hiss or hum. Even if you can’t hear it, when music is playing; you know it’s there…and you know, it’s masking something (the way, a really low noise-floor/black-background…seems to brings out more detail. But it’s not necessarily more resolution, but less noise). And I always thought, the DSJ…was built, to be DAC and pre-amp, as one box; and that’s certainly, how I intended to use it.

Hmmm…

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Andolink…what amp and speakers are you using; SE or Balanced ICs?

Thanks,

The DS Jr doesn’t need external cooling - the components are selected carefully to be comfortable at 100C steady-state, which it will never reach. e.g. the electrolytic capacitors are both designed for longer life and life at 40C higher than “normal” caps. The heat generation is fairly localized at the power supply heat sinks at the input and is a byproduct of using a linear power supply instead of the switching supplies that many units use.

Ted…you may have misunderstood my point.

I’m not saying, the DSJ does need a fan; or suggesting people look elsewhere, because it does.

I don’t have my DSJ yet (it’s on order); but I have owned other PSA products in the past (including the PerfectWave II), and found them to be of high quality and sonics (or I wouldn’t have ordered, the DSJ…“blind”, or “deaf” as the case may be).

What I was saying…in response to Netspecht-2s just-get-a-fan proposition; is I thought that was a backwards way, of looking at the product. If I were looking at a car…and I liked it, but it dripped oil; I wouldn’t allow the dealer to say “just keep a pan under it”…lol.

Now…I’m not sure, and I’ve asked; are about positioning of the units, for Netspecht-2 and Andolink. As stated…I don’t stack (haven’t, since I was a teenager); and my kit doesn’t go in a cabinet. If what they’re saying…is if you need (or prefer it) to use a cabinet; it can run a little hot…and therefore a fan might be helpful, if you have concerns. Then hopefully that’s a moot point for me.

What concerns me, a bit more; is that you didn’t vehemently…address and/or deny, the noise/hum issue.

Sorry about the misunderstanding.

I’ll repeat a post about the noise in the Jr and with DSD DACs in general:

There are threads about the noise floor (see below). Most people don’t have a problem. Most that did chose to address it with one or more of the recommendations. I’m sure some don’t wait until their unit is broken in before making up their minds. This is expected - but the DSs take longer than most pieces of kit to break in.

My most recent post on this topic:

https://forum.psaudio.com/t/fpga-improvements-in-redcloud/4482/56

In this thread:

https://forum.psaudio.com/t/dsd-dac-very-faint-high-frequency-noise/2476/8

An older DS Jr post - Since then Huron lowered ultrasonic noise:

https://forum.psaudio.com/t/from-junior-high-frequency-noise/3980/6

I connect the DSJ directly into a Simaudio Neo 340i (which I’m now using as a power amp) via XLR’s and it feeds my Dynaudio C1 Mk II’s and SVS sb12-nsd sub.

Ted…do you find the issue, to have anything to do; with the power-amp’s input impedance?

The reason I ask…is I’m considering, 2 or 3 mates; and if there’s a spec I should look for…I’d love to at least be aware of it.

Thanks,

Ted, your posts about this issue all use this same qualifier: “the noise shouldn’t be audible when playing at typical levels”

My problem is I’m not willing to use my music to mask noise that I otherwise can clearly hear. Obviously the listener is still hearing the noise but now mixed together with the music being played back.

Also, the prhase “typical levels” ignores the fact that not every listener listens to music of unvarying dynamic range like most rock, pop and country music. I listen almost exclusively to classical music and virtually everything I listen to has numerous passages of extremely quiet and/or delicate stuff going on that depends for its effect on having a black background. I had no problem at all hearing the background hiss/hum during these parts of several pieces I played using the DSJ.

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No, not power amp impedance. (In particular the DS and DS Jr are quite flat at about 100 Ohms, most power amps are 22k, 47, 100k Ohms so there’s not much bad interaction. Passive preamps are the worst offenders in that many have a (relatively) high and changing output impedance with frequency that can, for example, roll of the top end…)

Assuming that the basics are fine (nothing broken, no big groundloop problems, no other systemic problems…)

The most likely possibilities for noise problems with the DS and DS Jr are mismatched gains or sensitivity to ultrasonic noise.

If you have a 700W amp and horn speakers at best you’re wasting money on extra power handling capability (tho it can sound good.) But at worst you are far from the expected output level of the amp and will have to have a very low input signal. That will be much more sensitive to noise, ground loops, RF interference, etc.

Similarly if your preamp has a very high output and your amp is quite sensitive you’ll be using just the bottom of the preamp’s volume range and once again might be dealing with very low level signals along the path and hence more noise than necessary.

The DS and DS Jr have a good enough S/N ratio for systems that have fairly matched levels system. (They have similar noise floors to the equipment used to master most of the SACDs in the first decade or so.) But if you have extra sensitive speakers and too much gain otherwise in your system you may be using just the bottom end of the DS’s volume and therefor be much closer to the analog noise floor and needlessly hearing noise. The 20dB attenuator in the DS and DS Jr will knock the level down by 20dB which also knocks the noise down by 20dB which allows the rest of the DAC to be used with 40 ticks higher volume levels in systems with relatively large gain or sensitive speakers.

Most people have systems that one setting or the other of the 20dB attenuator will work with well.

There are some systems with out enough gain, so the music can’t get loud enough or lacks dynamics, but that’s not a noise issue.

There are some systems that are somewhere in the middle and without the 20dB attenuator are too loud and with it are too noisy. We added 3dB extra gain (106 on the volume) to help some of these systems. Others have put in inline attenuators between the DS and the amps (or preamp.)

The bottom line is that some systems will need a preamp to get the most out of the DS and/or DS Jr.

Many preamp and amp designs weren’t designed with ultrasonic noise in mind and react badly to the unexpected ultrasonic noise: I’m not knocking them, that just wasn’t a part of their design goals. Many have a wide enough linear bandwidth that some ultrasonic noise between 50 or 60kHz and 150kHz isn’t a problem. The level of ultrasonic noise in the DS and DS Jr is below the spec for SACDs (at least 20dB lower) but some systems don’t sound great with SACDs (on wider bandwidth players) either.

Once again a preamp may help in that many (most?) aren’t affected by ultrasonic noise but will pass less of it downstream. But I know from personal experience that there are also some systems where the preamp is the most sensitive and running the DS (or DS Jr) directly to the amps sounds much better.

No, it isn’t the case that most people are putting up with noise in their music (or their quiet music.) There are broad ranges of taste in music, but there are many systems out there that will play anything well at a good range of volumes. My previous post mentioned two potential system matching issues and the links (and follow on discussion) talk about some others. As I mentioned the signal to noise ratio of the DS is better than a lot of DSD mastering equipment (certainly not all, but much of the equipment used for DSD) but gain matching is a prime consideration of most of the recording chain up to the delivery of discs, vinyl,…

Still all things considered a few people that otherwise like the DS Jr have upgraded to the DS Sr for the extra 6dB of analog S/N ratio. Others have added (or deleted) a preamp.

In case some haven’t read the links above, upgrading to Redcloud also lowers the noise floor a little and that was enough of a change for some to no longer have to deal with noise while listening. Tho a recently purchased DS or DS Jr probably already has Redcloud on it, it’s still worth checking.

The bottom line is that I’m not recommending that anyone try to live with noise in their music, but I am saying that most have found acceptable modifications to their settings and or cables or other equipment so that that isn’t a problem.

And some can’t deal with the idea of extra noise even if they can’t hear it. That’s fine, I can’t deal with the fiddlelyness of vinyl so I don’t reap the possible benefits of it.

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@flac2dac

Within a cabinet, rear panel moved. Only thing stacked on the component is the AC Infinity T8 fan.

I use quiet low speed fans on all my major components. It works for me, backwards or not.

Update-- I followed Ted’s advice and changed the attenuator setting to “low” and, Voila!, noise problem gone. So now I can proceed with burn in and further evaluation.

Sound right out of the box is quite good but I’m sure it will evolve over the next several days.

The heat issue I’ll just ignore for now since Ted says the gear is designed to run at these temperatures. I’ll at least try raising the DSJ up on some one inch feet I’ve got.

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@andolink Glad you’ve reached the happy ending. Keep us updated of your burn-in process.

Thanks

Will do.

So I’m at about 15 hours of burn-in and there’s now definitely a noticeable change toward an opening up of the sound stage and better imaging. The disconcerting smallness of sound stage and congested quality to the sound right out of the box is rapidly disappearing. There’s still at this point however, a slight unnaturalness and overly bright quality to what I’m hearing compared to what my SGCD was delivering. But the burn-in so far is starting to really show very positive change happening so I’m excited.

About 22 hours now and instruments are now sounding tonally just right without any unnatural brightness while the sound stage and imaging continue to improve.

The DSJ is now eclipsing the performance of my SGCD.

And I was, at one time, a burn-in skeptic!

Is the default sample rate setting for the bridge on the Jr “NativeX” and is there a way to change it?

The Bridge is just an input interface. It does not change the sample rate. The DS Sr and Jr both convert everything (all inputs treated the same) to high rate (20x I believe) DSD. The sample rates cannot be changed (except by Ted in firmware). NativeX was a feature of the PWD Mk. II and not the Bridge (either B1 or B2).

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Dyn C1s…are FAR from sensitive; 85db if memory serves. So…the high attenuation, is the default?

Oh, wait; the 340i is an IA, yes? So…you’re just running the DSJ, as DAC??